im confused
 

hey i went to the dealer and saw two rx8s and whats weird is that they have a sticker right before thr rear wheels. the dealer said its a vinal sticker to protect aganst from rocks damaging the fenders. but i just wanted to know is that what they really do

Yup

Yes it is the same type material as the 3M clear bra as posted
it other threads used to protect paint from chipping.